The United States and its Arab allies will continue to foster rebel fighters in Syria to oust Islamic extremists and President Bashar Assad, Deputy National Security Adviser Tony Blinken said on Sunday.

The deputy national security adviser Tony Blinken on Sunday sharply rejected comparisons between the ongoing war against Islamic State of Iraq and the Levant and the Bush-era wars in Iraq and Afghanistan.

Deputy National Security Adviser Tony Blinken on Sunday pushed back against criticisms that a perceived weakness of President Barack Obama or his strategy in Syria led to Russia's incursion into Crimea.